Fiscal Note
No fiscal impact.
Title
Amending Sections 37.05(6)(b) and 37.09(3)(d)6.c. of the Madison General Ordinances to address design standards for certain Storm Sewer Systems.
Body
DRAFTER'S ANALYSIS: This ordinance updates the design standards for public and private storm sewer systems, requiring the storm sewer system in an enclosed depression to be designed to handle 100-year storm events. No standard currently exists for private systems on such lands, while the public standard currently applies to 25-year storm events.
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The Common Council of the City of Madison do hereby ordain as follows:
1. Subdivision (b) of Subsection (6) entitled “Additions to the Public Stormwater System” of Section 37.05 entitled “The Public Stormwater System” of the Madison General Ordinances is amended to read as follows:
“(b) A determination of the type of storm drainage system to be used shall be made by the Administrative Authority on the basis of required capacity, economics, and use of abutting lands. Additions to the Public Stormwater System shall, in general, be designed and constructed to convey stormwater, which would drain from the upstream lands as a result of a storm that could be expected to occur once in ten (10) years, except that culvert crossings in greenway drainage systems shall be designed for the twenty-five (25) year event peak flow.
Where, in the opinion of the Administrative Authority, a situation exists which will result in development or creation of an enclosed depression (no safe overflow path during times when the storm sewer is at capacity), and where the only outlet is the storm sewer system, then the storm sewer system shall be designed to handle the runoff that can be expected to result from a twenty five one hundred (25100) year storm event or larger depending on the risk of property damage and public safety, as determined by the Administrative Authority....
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